Chair frame



FIG. 1 is a top plan view of a chair frame showing the ornamental design thereof;

FIG. 2 is a side elevational view taken from the right in FIG. 1;

FIG. 3 is a side elevational view taken from the left in FIG. 1;

FIG. 4 is a front elevational view; and

FIG. 5 is a rear elevational view.

The bottom of the chair frame is conventional in appearance. 

The ornamental design for a chair frame, as shown and described. 